Question

我有一张死亡表，其中每个personID显示死亡。还有一栏有关死亡的原因以及他/她去世的日期。

我需要计算因疾病，意外，自杀等而死亡的所有人。

我希望我的输出是这样的：

| Illness | Accident | Suicide | | 32 | 55 | 3 |

我可以轻松创建这样的视图：

CREATE VIEW viewDeaths AS SELECT COUNT(personID) AS Illness WHERE Reason = 'Illness';

它会显示正确，但我如何在多个条件下进行？

主要目的是在C＃应用程序的图表上显示每个原因的不同值

Answer 1

只需使用多个子查询：

CREATE VIEW viewDeaths AS
    SELECT Illness = (SELECT COUNT(*) FROM dbo.Deaths d
                      WHERE d.Reason = 'Illness'),
           Accident = (SELECT COUNT(*) FROM dbo.Deaths d
                      WHERE d.Reason = 'Accident'),
           Suicide = (SELECT COUNT(*) FROM dbo.Deaths d
                      WHERE d.Reason = 'Suicide')

Answer 2

这样：

 CREATE VIEW viewDeaths AS
     SELECT Reason, COUNT(personID) AS Illness
    -- WHERE Reason IN (.....)
     GROUP BY Reason

Answer 3

由于它是一个视图，因此您无法使用动态SQL，因此静态PIVOT或CASE表达式将是最佳方式：

CREATE VIEW viewDeaths 
AS
SELECT  SUM(CASE WHEN Reason = 'Illness' THEN 1 ELSE 0 END) Illness,
        SUM(CASE WHEN Reason = 'Accident' THEN 1 ELSE 0 END) Accident,
        SUM(CASE WHEN Reason = 'Suicide' THEN 1 ELSE 0 END) Suicide 
FROM dbo.Deaths;

算在一个视图中

3 个答案: